THE GENESIS OF Ly\KE AGASSIZ/ 



I\ a j3aper read before the Geological Society of America 

 on December 28, last, entitled TJic Rdi7tioii hctivceii Ice-Lobes 

 South fro))i the U'isco//si// Driftless Area, Mr. Frank Leverett^ 

 appears to have made some very interesting records of the rela- 

 tive ages of the sheets of drift in Illinois and vicinity. As these 

 are directly in line with the observations made by me during the 

 past few years in ]Manitoba, and throughout the country north- 

 ward lying west of Hudson Bay, a few notes on the conclusions 

 to which these observations tend may be of interest in advance 

 of the publication of my detailed reports and maps by the Geo- 

 logical Survey of Canada. 



In a short paper published in the Geological Magazine for 

 September 1894, based on the explorations of 1892 and 1893, 

 the writer outlined the existence, during the Glacial Period, of 

 a great glacial center or gathering ground lying comparatively 

 close to the w^est coast of Hudson Bay, from which the ice radi- 

 ated in all directions ; eastward into the basin of Hudson Bay, 

 which was probably an open body of water then as it is now, 

 and furnished the moisture for the immense precipitation of snow 

 a short distance to the west of it ; southward towards Manitoba 

 and the Great Plains ; westward towards the Athabasca-Macken- 

 zie Valley and the Rocky Mountains ; northwestward and north- 

 ward 3 toward the Arctic Ocean. 



A second expedition by the writer through the same or 

 adjoining country in 1894 served to corroborate and strengthen 

 the conclusions reached in the preceding years. At or near the 



" Published by permission of the Director of the Geological Survey of Canada. 



= Abstract in American Geologist, f'ebruary 1896. p. 102. 



3 Notes to accompany a Geological Map of the Northern portion of the Dominion 

 of Canada, by George M. Dawson, Ann. Rep. Geol. Sur. Can., Vol. II, 1886, Part R. 

 i>- 57- 



811 



